Hot-dip galvanized steel strip - Technical Terms of Delivery
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Hot-dip galvanized steel strip Technical Terms of Delivery voestalpine Stahl GmbH www.voestalpine.com/stahl
Contents
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Introduction 5
Hot-dip galvanized steel strip with zinc coating 6
Steel grades 6
Mild steels for cold forming 6
Structural steels 12
High-strength steels for cold forming 16
Micro-alloyed steels 17
Bake-hardening steels 22
High-strength IF steels 24
2
Dual-phase steels 28
Complex-phase steels 33
TRIP steels 35
Zinc coating groups 38
Surface 39
Surface of the zinc coating 39
Surface quality 39
Surface type 40
Subsequent surface treatment 41
Available dimensions 42
Inspection and Testing 43
Test unit 43
Sample-taking 43
Performance of tests 43
Repeat tests 44Processing information 45
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Forming 45
Joining 45
Thermal rating 46
Suitability for the application of coatings 46
General notes 47
Fretting corrosion 47
Darkening 47
Formation of white rust 47
Flatness 48
Hot-dip galvanized steel strip with
zinc/iron-coating (Galvannealed) 49
3
Steel grades 49
ZF coating groups 50
Surface 51
Surface quality 51
Surface type 51
Subsequent surface treatment 52
Available dimensions 53
Inspection and Testing 54
Processing information 55
Joining 55
Forming 55
Suitability for the application of coatings 55T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
General notes 56
Fretting corrosion 56
Formation of white rust 56
Hot-dip galvanized steel strip with
zinc magnesium coating 57
Steel grades 57
ZM coating groups 58
Terms of delivery 59
4
Surface 72
Subsequent surface treatment 72
Application and processing instructions 73
Appendix 74
Pertinent standards 74Introduction
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Hot-dip galvanized steel strip is a hot-dip refined product with Zn, ZnMg or ZnFe coating on both
sides. The corresponding short forms are Z, ZM and ZF.
Hot-dip refining is based on a modified Sendzimir process. This is a high-integration manufacturing
process that consists of the following main process steps: Cleaning the full-hard strip (dry cleaning
and/or cleaning with easy reducing furnace atmosphere), recrystallizing annealing, coating by dip-
ping into a fusion-liquid bath and adjustment of the thickness with air or nitrogen blow-off, finishing
and/or straightening by stretching for the adjustment of mechanical properties, surface and flatness,
post-treatment, inspection and marking. All these processes run in continuous operation mode with
a continuous steel strip.
These Technical Terms of Delivery apply to hot-dip galvanized strip made of
p Mild steels for cold forming,
p Structural steels and
p High-strength steels suitable for cold forming.
5
These terms of delivery are to provide information to the customer on the production program of our
hot-dip galvanizing lines at the Linz site and serve as a guideline for ordering and processing. In accor-
dance with these Technical Terms of Delivery, hot-dip coated and galvanized steel strip complies with
generally applicable guidelines as described in the pertinent standards. You will find a comparison of
the standards in the Appendix.
Market requirements have reached a degree of complexity with regard to applications that would far
exceed the limitations of these Terms of Delivery if every detail were taken into account. For this rea-
son we ask that you address any questions to your respective commercial or technical contact partner.
They will ensure that you receive an adequate answer.Hot-dip galvanized steel strip
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
with zinc coating
Steel grades
The following contains a general description of the available steel grades and their respective areas
of application.The chemical constitution depends on the selected steel grade and is available upon
request. The mechanical properties, the available coatings and surfaces can be found in the respec-
tive tables.
Mild steels for cold forming
DX51D (machine crimping quality)
is suitable for the production of simple shapes such as trapezoid shapes and corrugated iron sheets as
well as for simple manual forming procedures.
6
DX52D (drawing quality)
can be considered for complex sections, embossing and drawn components.
DX53D (deep-drawing quality)
is used for medium requirements on formability such as deep drawing.
DX54D (special deep-drawing quality)
is designed for the special requirements of formability and deep drawability.
DX56D (special deep-drawing quality)
is designed for the most demanding forming requirements.
DX57D (extra special deep-drawing quality)
was developed for extremely high forming behavior requirements, in particular for extreme deep-
drawing strain and for the manufacturing of complicated press parts in rapid processing and highly
automated press lines.
The DX51D, DX52D, DX53D, DX54D, DX56D and DX57D steel grades are delivered according to
their mechanical properties. The values for the mechanical properties apply for a period of
p One month for steel grades DX51D and DX52D from the time they are made ready for dispatch
p Six months for steel grades DX53D, DX54D, DX56D and DX57D from the time they are made ready
for dispatch
Alternatively, agreement can be made on specific material properties for the manufacture of a parti-
cular component.Mechanical properties 1)
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Mild steels for cold forming
Steel grade 0.2% Yield Tensile strength Fracture elongation 4) Vertical Work hardening Zinc coating
point 2) Rm A80 anisotropy 5) 6) exponent 5) group
Rp 0.2 [MPa] [%] r n10 – 20 (UE)
[MPa] min. min. min.
DX51D - 270 – 500 22 - - Z 70 – Z 600 7)
DX52D 140 – 300 3)
270 – 420 26 - - Z 70 – Z 600 7)
DX53D 140 – 260 270 – 380 30 - - Z 70 – Z 600 7)
DX54D 120 – 220 260 – 350 36 1.6 0.18 Z 70 – Z 275
DX56D 120 – 180 260 – 350 39 1.9 5) 0.21 Z 70 – Z 275
DX57D 120 – 170 260 – 350 41 2.1 5)
0.22 Z 70 – Z 275
1)
Values transverse to rolling direction.
2)
If the yield point is pronounced, the lower yield point ReL applies.
3)
This value applies only to re-rolled products (MB and MC surfaces).
4)
Minimum fracture elongation values are minimized by 2 units for product thicknesses of ≤ 0.7 mm.
7
5)
Warranty values for r are minimized by 0.2 for product thicknesses of > 1.5 mm and for product thicknesses of > 2.0 mm by 0.4.
6)
Values for r are minimized by 0.2 for product thicknesses of > 0.7 mm and n by 0.01.
7)
Coating profiles above Z 275 available upon request.Available dimensions
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
DX51D, DX52D
Available dimensions mild steels for cold forming
Ordered strip thickness (mm)
4.00
3.50
MC surface for automotive
industry not possible.
3.00
8
2.50
2.00
1.50
1.00
0.50
0.00
700 800 900 1000 1100 1200 1300 1400 1500 1600
Ordered strip width (mm)
The graphics refer to thickness values with symmetrical thickness tolerances.
The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
Please contact our sales departments for widths below 900 mm (production scheduling for
center slitting and longitudinal slitting lines).T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
DX53D
Available dimensions mild steels for cold forming
Ordered strip thickness (mm)
4.00
3.50
3.00
9
2.50
2.00
1.50
MC surface up to a maximum of 1.2 mm in
1.00
thickness not possible for automotive industry.
0.50
0.00
700 800 900 1000 1100 1200 1300 1400 1500 1600
Ordered strip width (mm)
The graphics refer to thickness values with symmetrical thickness tolerances.
The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
Please contact our sales departments for widths below 900 mm (production scheduling for
center slitting and longitudinal slitting lines).T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
DX54D, DX56D, DX57D
Available dimensions mild steels for cold forming
Ordered strip thickness (mm)
4.00
3.50
3.00
10
2.50
2.00
1.50
MC surface up to a maximum of 1.5 mm in
thickness not possible for automotive industry.
1.00
0.50
0.00
700 800 900 1000 1100 1200 1300 1400 1500 1600
Ordered strip width (mm)
The graphics refer to thickness values with symmetrical thickness tolerances.
The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
Please contact our sales departments for widths below 900 mm (production scheduling for
center slitting and longitudinal slitting lines).Freedom of flow lines
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
It may be necessary to reroll the products in order to avoid the formation of flow lines during cold
rolling. The tendency toward the formation of flow lines can occur once again after some time, for
which reason it is in the interest of the user to process the products as soon as possible. Freedom of
flowing figures on MB and MC surfaces is maintained for the following duration after the material
has been made ready for dispatch:
p One month for steel grades DX51D and DX52D
p Six months for steel grades DX53D, DX54D, DX56D and DX57D
Coil break freedom
Rerolling or straightening through product stretching may be necessary for specific coil break freedom
requirements. The order must specify any coil break freedom requirement.
11Structural steels
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Structural steels are supplied with guaranteed minimum yield strengths in steel grades S220GD
through S350GD. These steel grades are suitable for all easy forming procedures such as crimping,
edging and profiling. They are not, however, intended for stresses such as those caused by deep
drawing. Depending on the strength class, the increased tendency toward elastic recovery during
the adjustment of machinery must be taken into consideration. Formability may be diminished
when these grades are stored for a longer period of time. Prompt processing after the material has
been made ready for dispatch is in the interest of the customer. The order must specify any coil
break freedom requirement.
Mechanical properties 1)
Structural steels
Steel grade 0.2% Yield point 2) Tensile strength 3) Fracture elongation 4) Zinc coating
Rp 0.2 Rm A80 group
[MPa] [MPa] [%]
min. min.
12
S220GD ≥ 220 300 20 Z 70 – Z 600 5)
S250GD ≥ 250 330 19 Z 70 – Z 600 5)
S280GD ≥ 280 360 18 Z 70 – Z 600 5)
S320GD ≥ 320 390 17 Z 70 – Z 600 5)
S350GD ≥ 350 420 16 Z 70 – Z 600 5)
1)
Values longitudinal to rolling direction.
2)
The upper yield point ReH applies when the yield point is pronounced.
3)
A maximum range of 140 MPa can be calculated for the upper limit of tensile strength.
4)
Minimum fracture elongation values are minimized by 2 units for product thicknesses of ≤ 0.7 mm.
5)
Coating profiles above Z 275 available upon request.Available dimensions
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
S220GD, S250GD, S280GD
Available dimensions structural steels
Ordered strip thickness (mm)
4.00
3.50
MC surface for automotive
industry not possible.
3.00
13
2.50
2.00
1.50
1.00
0.50
0.00
700 800 900 1000 1100 1200 1300 1400 1500 1600
Ordered strip width (mm)
The graphics refer to thickness values with symmetrical thickness tolerances.
The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
Please contact our sales departments for widths below 900 mm (production scheduling for
center slitting and longitudinal slitting lines).T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
S320GD
Available dimensions structural steels
Ordered strip thickness (mm)
4.00
3.50
MC surface for automotive
industry not possible.
3.00
14
2.50
2.00
1.50
1.00
0.50
0.00
700 800 900 1000 1100 1200 1300 1400 1500 1600
Ordered strip width (mm)
The graphics refer to thickness values with symmetrical thickness tolerances.
The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
Please contact our sales departments for widths below 900 mm (production scheduling for
center slitting and longitudinal slitting lines).T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
S350GD
Available dimensions structural steels
Ordered strip thickness (mm)
4.00
3.50
MC surface for automotive
industry not possible.
3.00
15
2.50
2.00
1.50
1.00
0.50
0.00
700 800 900 1000 1100 1200 1300 1400 1500 1600
Ordered strip width (mm)
The graphics refer to thickness values with symmetrical thickness tolerances.
The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
Please contact our sales departments for widths below 900 mm (production scheduling for
center slitting and longitudinal slitting lines).High-strength steels for cold forming
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
In addition to the mild steels, high-strength steel grades with yield strengths ranging from 160 to 500
MPa are available and are suitable for cold forming with less forming stress as well as for very difficult
forming procedures. Based on specifically coordinated steel analyses and production conditions, vari-
ous series of steel grades are available that lend themselves, depending on the steel grade, to specific
applications, particularly in the automotive industry. The higher yield point and the excellent forming
properties provide a significant potential for weight reduction.
The chemical composition of the substrate is adapted to the welding properties and is available
upon request. The maximum concentrations of base material elements correspond to the limit
values determined in EN 10346 for the respective grades (tables available in the Appendix).
The guaranteed mechanical parameters listed in the following sections are applicable to tests in
transverse direction to rolling. The mechanical parameters apply for a time period of three months
for all steels with guaranteed bake-hardening effect and six months for all other high-strength steel
grades from the time they are made ready for dispatch. Freedom of flow lines is guaranteed for this
period of time for Surface Type C orders. This does not apply to micro-alloyed steels.
16
The yield strength increased by the heat effect (so-called bake-hardening effect) is determined in
accordance with DIN EN 10325.
It can generally be assumed that increasing yield stress and decreasing sheet thickness lead to a
tendency towards necking, wrinkling and tears as a consequence of forming, which also leads to
form inaccuracy as a result of elastic recovery. In contrast with mild steels, the forming conditions
must be adjusted to the respective steel grade.
If the steel grades listed in the following sections do not fulfill customer requirements, please send a
material inquiry. Many high-strength steel grades are still being developed. More innovative develop-
ments will make additional steel grades available that have not yet been included in these Technical
Terms of Delivery.
Some of these steel grades have already been included in these Technical Terms of Delivery for infor-
mation purposes only. Such products are delivered following technical review upon request.Micro-alloyed steels
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Refined micro-alloyed steels with a guaranteed yield strength of between 260 and 500 MPa cover
the upper range of the conventional high-strength steel grade series and are suitable for moderate to
medium forming stress.
Steel grades HX260LAD through HX500LAD are generally based on the stability-increasing effect
of micro-alloyed additions (niobium or niobium with titanium). Grain refinement, age hardening and
the alloying of further strength-increasing elements, essentially manganese, are implemented in or-
der to achieve the desired strength.
The main areas of application for micro-alloyed steels are structural components in the automotive
industry such as safety-related elements in the passenger compartment, side members or bumpers.
Micro-alloyed steels are also excellently suited for the manufacturing of high-strength special
sections. Upon special request, micro-alloyed hot-dip galvanized steel grades can be used as an
alternative in guaranteeing the mechanical parameters in longitudinal direction. In this case the
guaranteed range of yield strength correspondingly shifts to a lower range by around 20 MPa. The
tensile strength values also change to lower values for longitudinal samples by around 10 MPa. The
17
guaranteed value for fracture elongation is correspondingly raised by 1%.
Mechanical properties 1)
Micro-alloyed steels
Steel grade 0.2% Yield point 2) Tensile strength 3) Fracture elongation 4) Zinc coating
Rp 0.2 Rm A80 group
[MPa] [MPa] [%]
min. min.
HX260LAD 260 – 330 350 – 430 26 Z 70 – Z 600 4)
HX300LAD 300 – 380 380 – 480 23 Z 70 – Z 600 4)
HX340LAD 340 – 420 410 – 510 21 Z 70 – Z 600 4)
HX380LAD 380 – 480 440 – 560 19 Z 70 – Z 600 4)
HX420LAD 420 – 520 470 – 590 17 Z 70 – Z 600 4)
HX460LAD 460 – 560 500 – 640 15 Z 70 – Z 275
HX500LAD 500 – 620 530 – 690 13 Z 70 – Z 275
1)
Values transverse to rolling direction.
2)
The lower yield point ReL applies when the yield point is pronounced.
3)
Lower minimum values by two percent are permissible for thicknesses of ≤ 0.7 mm
4)
Coating profiles above Z 275 available upon request.Available dimensions
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
HX260LAD, HX300LAD, HX340LAD
Available dimensions micro-alloyed steels
Ordered strip thickness (mm)
4.00
3.50
MC surface for automotive
industry not possible.
3.00
18
2.50
2.00
1.50
1.00
0.50
0.00
700 800 900 1000 1100 1200 1300 1400 1500 1600
Ordered strip width (mm)
The graphics refer to thickness values with symmetrical thickness tolerances.
The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
Please contact our sales departments for widths below 900 mm (production scheduling for
center slitting and longitudinal slitting lines).T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
HX380LAD, HX420LAD
Available dimensions micro-alloyed steels
Ordered strip thickness (mm)
4.00
3.50
MC surface for automotive
industry not possible.
3.00
19
2.50
2.00
1.50
1.00
0.50
0.00
700 800 900 1000 1100 1200 1300 1400 1500 1600
Ordered strip width (mm)
The graphics refer to thickness values with symmetrical thickness tolerances.
The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
Please contact our sales departments for widths below 900 mm (production scheduling for
center slitting and longitudinal slitting lines).T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
HX460LAD
Available dimensions micro-alloyed steels
Ordered strip thickness (mm)
4.00
3.50
3.00
20
2.50
2.00
MC surface for automotive industry not possible.
1.50
1.00
0.50
0.00
700 800 900 1000 1100 1200 1300 1400 1500 1600
Ordered strip width (mm)
The graphics refer to thickness values with symmetrical thickness tolerances.
The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
Please contact our sales departments for widths below 900 mm (production scheduling for
center slitting and longitudinal slitting lines).HX500LAD
Available dimensions micro-alloyed steels
Available dimensions upon request.
21 T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2Bake-hardening steels
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
By fine-tuning alloy compositions and adapting process parameters it is possible to produce hot-dip
coated bake-hardening steels that are characterized by their significant increase in yield strength
in the course of paint baking (bake-hardening effect). This increase in yield strength in the series of
steels from HX180BD to HX300BD is achieved by ensuring that a defined amount of carbon remains
dissolved in the steel.This carbon is released during heat treatment in the course of paint baking,
which leads to an increase in strength.
The hot-dip coated bake-hardening steels are also characterized by a very high degree of forma-
bility, which makes possible a wide range of applications in the manufacture of bodies in white.
Depending on the forming stress, the entire range of yield strengths can be used in interior compo-
nents for bodies in white. The HX180BD and HX220BD steel grades are also especially suitable for
exterior bodies in white because the bake-hardening effect in these steels when compared to mild
steels yields significantly improved dent resistance.
Mechanical properties 1)
Bake-hardening steels
22
Steel grade 0.2% Yield Tensile Fracture Vertical Work Bake- Zinc coating
point 2) strength elongation 3) anisotropy hardening hardening group
Rp 0.2 Rm A80 min. r exponent value BH2
[MPa] [MPa] [%] min. n10 – 20 (UE) [MPa] min.
min.
HX180BD 180 – 240 290 – 360 34 1.5 0.16 35 Z 70 – Z 200
HX220BD 220 – 280 320 – 400 32 1.2 0.15 35 Z 70 – Z 200
HX260BD 260 – 320 360 – 440 28 - - 35 Z 70 – Z 200
HX300BD 300 – 360 400 – 480 26 - - 35 Z 70 – Z 200
1)
Values transverse to rolling direction.
2)
The lower yield point ReL applies when the yield point is pronounced.
3)
Lower minimum values by two percent are permissible for thicknesses of ≤ 0.7 mm.Available dimensions
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
HX180BD, HX220BD, HX260BD, HX300BD
Available dimensions bake-hardening steels
Ordered strip thickness (mm)
4.00
3.50
3.00
23
2.50
2.00
1.50
1.00
MC surface up to a maximum of 1.0 mm in
thickness not possible for automotive industry.
0.50
0.00
700 800 900 1000 1100 1200 1300 1400 1500 1600
Ordered strip width (mm)
The graphics refer to thickness values with symmetrical thickness tolerances.
The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
Please contact our sales departments for widths below 900 mm (production scheduling for
center slitting and longitudinal slitting lines).High-strength IF steels
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Hot-dip coated, higher-strength, interstitial-free steels are based on a vacuum-decarburized IF base
material stabilized with Ti and/or Nb, which leads to an ideal condition for extremely difficult forming
procedures with deep-drawing stresses. The adjustment of the required ranges of strength is carried
out by alloying P and Mn in the course of solid-solution strengthening. This basic IF analysis lends
this group of steel grades higher values of vertical anisotropy (r value) when compared to other steel
grades of similar strength. This vertical anisotropy value is an important parameter for deep-drawing
strain. The high r values in diagonal direction lead to a certain degree of isotropic behavior during the
forming of this series of steel grades.
The main area of application for high-strength interstitial-free steels is found in formed automotive
components, such as in the interior wheel arch, side members that are difficult to form, or in bottom
plates in the area of the tunnel. For this reason, profiling applications seem to be less sensible because
no deep-drawing stress occurs.
Mechanical properties 1)
High-strength IF steels
24
Steel grade 0.2% Yield point Tensile strength Fracture Vertical Work hardening Zinc coating
Rp 0.2 Rm elongation 2) anisotropy 3) exponent group
[MPa] [MPa] A80 r n10 – 20 (UE)
[%] min. min.
min.
HX160YD 160 – 220 300 – 360 37 1.9 0.20 Z 70 – Z 200
HX180YD 180 – 240 330 – 390 34 1.7 0.18 Z 70 – Z 200
HX220YD 220 – 280 340 – 420 32 1.5 0.17 Z 70 – Z 200
HX260YD 260 – 320 380 – 440 30 1.4 0.16 Z 70 – Z 200
HX300YD 300 – 360 390 – 470 27 1.3 0.15 Z 70 – Z 200
1)
Values transverse to rolling direction.
2)
Lower minimum values by two percent are permissible for thicknesses of ≤ 0.7 mm.
3)
The guaranteed value is minimized by 0.2 units for product thicknesses > 1.5 mm.Available dimensions
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
HX160YD, HX180YD, HX220YD
Available dimensions higher-strength IF steels
Ordered strip thickness (mm)
4.00
3.50
3.00
25
2.50
2.00
1.50
1.00
MC surface up to a maximum of 1.0 mm in
thickness not possible for automotive industry.
0.50
0.00
700 800 900 1000 1100 1200 1300 1400 1500 1600
Ordered strip width (mm)
The graphics refer to thickness values with symmetrical thickness tolerances.
The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
Please contact our sales departments for widths below 900 mm (production scheduling for
center slitting and longitudinal slitting lines).T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
HX260YD
Available dimensions higher-strength IF steels
Ordered strip thickness (mm)
4.00
3.50
3.00
26
2.50
2.00
1.50
1.00
MC surface up to a maximum of 1.0 mm in
thickness not possible for automotive industry.
0.50
0.00
700 800 900 1000 1100 1200 1300 1400 1500 1600
Ordered strip width (mm)
The graphics refer to thickness values with symmetrical thickness tolerances.
The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
Please contact our sales departments for widths below 900 mm (production scheduling for
center slitting and longitudinal slitting lines).HX300YD
Available dimensions higher-strength IF steels
Available dimensions upon request.
27 T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2Dual-phase steels
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Dual-phase steels consist of a multi-phase base material microstructure of which the main com-
ponents are ferrite (80–90%) and martensite (10–20%). Other phases may be included in smaller
amounts.
The special characteristic of dual-phase steels is that particularly low yield ultimate ratios can be ob-
tained with high ultimate tensile strengths. As related to the high level of tensile strength, high de-
grees of fracture elongation and hardening exponents can also be achieved. Because of pronounced
offset strain hardening, particularly at the beginning of forming, dual-phase steels are especially
predestined for forming stress in the stretch forming area. An additional positive characteristic is the
achievable bake-hardening effect, which leads to an additional increase in the yield strength after
forming during paint baking.
Based on the characteristic property profile of dual-phase steels, this series of steel grades is especially
suitable for crash-relevant structural parts such as side members, crossmembers, and stiffeners for A,
B or C columns. Dual-phase steels demonstrate special potential in significantly contributing to weight
reduction as well as increased passive safety in automotive structures.
Mechanical properties 1)
28
Dual-phase steels
Steel grade 0.2% Yield Tensile strength Fracture Work hardening Bake-hardening Zinc coating
point 2) Rm elongation 3) exponent value group
Rp 0.2 [MPa] A80 n10 – 20 (UE) BH2 [MPa]
[MPa] min. [%] min. min.
min.
HCT450X 260 – 340 450 27 0.16 30 Z 70 – Z 200
HCT500X 300 – 380 500 23 0.15 30 Z 70 – Z 200
HCT600X 340 – 420 600 20 0.14 30 Z 70 – Z 200
HCT780X 450 – 560 780 14 - 30 Z 70 – Z 200
HCT980X 4) 600 – 750 980 10 - 30 Z 70 – Z 200
1)
Values transverse to rolling direction.
2)
The lower yield point ReL applies when the yield point is pronounced.
3)
Lower minimum values by two percent are permissible for thicknesses of ≤ 0.7 mm.
4)
Available dimensions upon request.Available dimensions
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
HCT450X
Available dimensions dual-phase steels
Ordered strip thickness (mm)
4.00
3.50
3.00
29
2.50
2.00
MC surface for automotive industry available
upon request.
1.50
1.00
0.50
0.00
700 800 900 1000 1100 1200 1300 1400 1500 1600
Ordered strip width (mm)
The graphics refer to thickness values with symmetrical thickness tolerances.
The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
Please contact our sales departments for widths below 900 mm (production scheduling for
center slitting and longitudinal slitting lines).T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
HCT500X
Available dimensions dual-phase steels
Ordered strip thickness (mm)
4.00
3.50
3.00
30
2.50
2.00
MC surface for automotive industry available
upon request.
1.50
1.00
0.50
0.00
700 800 900 1000 1100 1200 1300 1400 1500 1600
Ordered strip width (mm)
The graphics refer to thickness values with symmetrical thickness tolerances.
The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
Please contact our sales departments for widths below 900 mm (production scheduling for
center slitting and longitudinal slitting lines).T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
HCT600X
Available dimensions dual-phase steels
Ordered strip thickness (mm)
4.00
3.50
3.00
31
2.50
2.00
MC surface for automotive industry available
upon request.
1.50
1.00
0.50
0.00
700 800 900 1000 1100 1200 1300 1400 1500 1600
Ordered strip width (mm)
The graphics refer to thickness values with symmetrical thickness tolerances.
The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
Please contact our sales departments for widths below 900 mm (production scheduling for
center slitting and longitudinal slitting lines).HCT780X, HCT980X
Available dimensions dual-phase steels
Available dimensions upon request.
32 T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2Complex-phase steels
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
The availability of complex-phase steel grades with increased yield point and minimum tensile
strength is a meaningful addition to the dual-phase range of steels. These steel grades are defined
with minimum yield strengths from 780 to 980 MPa. The microstructure of these advanced high-
strength steels is characterized by the fact that the martensite particles are distributed in the soft
ferrite matrix, whereas bainite phases can also occur in addition to the martensite.
In comparison to the dual-phase steels, this series of steel grades is characterized by a higher yield
strength at the same tensile strength and thus a higher yield-strength ratio and a somewhat lower
possibility of guaranteeing certain levels of fracture elongation. The complex-phase steels are also
characterized by pronounced work-hardening behavior, even though this is not as noticeable as it is
with the dual-phase steels. The additional benefit that strength increases in the course of heat treat-
ment during paint baking, remains as it does in dual phase steels.
Structural parts with lower forming stress show higher yield strengths with this series of steel grades
in comparison to the dual-phase grades. This can be compensated through a simpler component
design aimed at increasing strength resulting from stronger deformation. Partially martensitic steels
are predestined for high-strength special sections and safety-related structural components with lo-
33
wer forming stresses.
This grade also lends itself well to the manufacture of foldable parts and roll-formed components.
Mechanical properties 1)
Complex-phase steels
Steel grade 0.2% Yield point Tensile strength Fracture elongation Bake-hardening Zinc coating
Rp 0.2 Rm A80 value group
[MPa] [MPa] [%] BH2 [MPa]
min. min. min.
HCT780C 2) 600 – 750 780 10 30 Z 70 – Z 200
HCT980C 2)
800 – 950 980 6 30 Z 70 – Z 200
1)
Values transverse to rolling direction.
2)
Available dimensions upon request.Available dimensions
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
HCT780C, HCT980C
Available dimensions complex-phase steels
Available dimensions upon request.
34TRIP steel
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
TRIP (transformation-induced plasticity) steels are comprised of a ferritic matrix (roughly 75%), bainite
(approximately 10%) and metastable residual austenite (up to 15%). The hard phase (bainite) and stabi-
lity of the austenite during forming influence the spectrum of mechanical properties.
Transformation-induced plasticity means that the metastable “soft” austenite is transformed into “hard”
martensite during plastic forming (deep drawing). This makes local constriction difficult and increases
the values for uniform elongation. This is the basis for the well-known excellent formability of TRIP
steels with high initial tensile strength of the respective basic strength. The increased bake-hardening
effect achieved by temperature treatment additionally increases the potential weight savings. This se-
ries of steel grades is available in two classes with minimum tensile strengths of 690 MPa and 780 MPa.
TRIP steels with 980 MPa are currently under development and can be delivered upon request. TRIP
steels are particularly suited to crash-relevant applications or safety parts with increased forming stress
in the manufacturing process.
Mechanical properties 1)
TRIP steels
35
Steel grade 0.2% Yield point Tensile strength Fracture Work hardening Bake-hardening Zinc coating
Rp 0.2 Rm elongation exponent value BH2 group
[MPa] [MPa] A80 min. n10 – 20 (UE) [MPa] [MPa] min.
min. [%] min.
HCT600T 400 – 520 600 25 - 40 Z 70 – Z 200
HCT690T 430 – 550 690 23 0.18 40 Z 70 – Z 200
HCT780T 470 – 600 780 21 0.16 40 Z 70 – Z 200
1)
Values transverse to rolling direction.Available dimensions
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
HCT600T, HCT690T
Available dimensions TRIP steels
Ordered strip thickness (mm)
4.00
3.50
3.00
36
2.50
2.00
MC surface for automotive industry
not possible.
1.50
1.00
0.50
0.00
700 800 900 1000 1100 1200 1300 1400 1500 1600
Ordered strip width (mm)
The graphics refer to thickness values with symmetrical thickness tolerances.
The maximum width is reduced by 20 mm if the width tolerance is limited or if the edge is cut.
Please contact our sales departments for widths below 900 mm (production scheduling for
center slitting and longitudinal slitting lines).HCT780T
Available dimensions TRIP steels
Available dimensions upon request.
37 T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2Zinc coating groups
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
The available zinc coatings and their respective minimum values are shown in the following table.
The desired zinc coating group (corresponds to the zinc coating in g/m 2 on both sides) is specified in
the order.
Coating groups
Zinc coating in g/m2 on both sides min. Zinc coating thickness in µm per side
Zinc coating group
Triple surface test Single surface test Typical value Area
Z 100 100 85 7 5 – 12
Z 140 140 120 10 7 – 15
Z 200 200 170 14 10 – 20
Z 225 225 195 16 11 – 22
Z 275 275 235 20 15 – 27
Z 350 350 300 25 19 – 33
38
Z 450 450 385 32 24 – 42
Z 600 600 510 42 32 – 55
A zinc coating of 100 g/m 2 (on both sides) corresponds to a zinc layer thickness of approximately
7 µm per side. The respective possibilities for delivery, depending on the steel grade, are shown in
the steel grade tables.
The Z350–Z600 zinc coating group can only be delivered with an NA surface.
Special coatings are available upon request in special cases only.
Different zinc coating for each side (different degree of galvanization) can be delivered upon reque-
st. In the event of differential galvanizing, in consequence of production, the surface of the side with
the lesser amount of zinc coating may have a different appearance than the side with the greater
amount of zinc coating.
The zinc coating is monitored continuously by means of an x-ray fluorescent technique.Surface
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Zinc coating surface
The surface of the zinc coating is determined by the design, type and surface treatment. Hot-dip
galvanized steel strip Zn with surface NA and chemically passivated is delivered in the event the
order does not contain any additional information on the desired surface. Possible dimension-related
limitations with respect to the surface can be found in the limit curves.
The zinc coating does not include intentionally added lead concentrations (lead-free hot-dip galva-
nized strip). Finally, with respect to the environmental compatibility of the product, this measure was
implemented by voestalpine Stahl GmbH and excludes the delivery of hot-dip galvanized strip with
distinctive spangle formation (large spangles).
39
Surface quality
Normal quality (N)
Zinc crystals occur in varying brightness and size, depending on prevalent galvanizing conditions.
The usability of the product is not influenced by these crystals. The grade is delivered even if no pre-
ferences regarding surface quality are specified. We reserve the right to ship rerolled material.
Small spangle (M)
The surface shows small to macroscopic non-visible spangles caused by targeted influence on soli-
dification. The products may show a slightly different body structure on the surface from coil to coil
and as well as in one coil. Delivery of slightly rerolled strip in surface type MA (explicitly not desired
by the customer) must be specified in the order.Surface type
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
There are three different surface types.
Typical surface A
Small pits, different spangle sizes, dark spots, stripe-shaped marks, and small passivation defects are
acceptable on this type of surface. Straightening and bending fractures and zinc runoff waves may
be visible.
Improved surface B
This type of surface is attained by rerolling. A small number of fractures in stretch forming direction,
finishing imprints, scratches, impressions, spangle structures, zinc runoff waves and slight passiva-
tion errors may occur on the inspected side. The uninspected side of the material must at least meet
the requirements of Surface Type A.
Best surface C
This type of surface is also attained by rerolling. The inspected side does not negatively impact the
uniform appearance of a paint coat. The other side of the material must at least meet the require-
ments of Surface Type B. Surface Type C is available for delivery up to a maximum of 1.5 mm.
40
Roughness
As a standard, Surface Types B and C are delivered with a medium roughness value ranging bet-
ween 0.6 and 1.9 µm. Determination of the mean Ra roughness value is subject to a wavelength limit
of 2.5 mm in accordance with EN 10049 (standard length of 12.5 mm).
Where specially required, the delivery of limited roughness values may be specified. Special qualities
include smooth, half mat or mat.
Roughness
Design Median roughness value Ra (µm)
Standard 0.6 – 1.9
Special design: smooth 0.9 max.
Special design: half-mat 0.6 – 1.4
Special design: mat 1.0 – 1.9
The desired quality must be specified in the order. Discussion of requirements with regard to surface
appearance is recommended when a smooth surface has been selected. Smooth surface with glossy
appearance (especially smooth) is subject to specification in the order.Subsequent surface treatment
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Hot-dip galvanized steel strip is delivered only with surface protection on account of the increased pro-
pensity toward white rust. The following surface treatment procedures are usual:
p Chromium-free passivated (C)
p Oiled (O)
p Chromium-free passivated and oiled (CO)
Chromium-free passivated (C)
To the extent not specifically agreed, hot-dip galvanized steel strip is delivered with normal sur-
faces (NA) with small spangles (MA) and chromium-free passivated. Local discoloration caused by
chromium-free passivation is permitted and does not negatively influence other quality properties.
Chromium-free passivation may influence further surface treatments carried out by the customer, for
example phosphating. Another surface treatment is recommended in such cases.
Oiled (O)
Surfaces MB and MC are usually delivered in oiled condition. The oil layer can be removed with
suitable zinc-sparing degreasing agents. Depending on the intended treatment stress, two different
41
standard coatings can be ordered: slightly oiled as a temporary form of corrosion protection and as
a forming aid for medium forming stress, oiled for very heavy forming stress. Although the oil is
distributed evenly, a certain degree of oil will invariably spread across the length and width of the
strip and some oil from heavily oiled strip will be shed from the surface during transportation and
storage. This is technically unavoidable.
Oil amounts
Slightly oiled approx. 0.7 g/m2 per side
Oiled approx. 1.2 g/m2 per side
Chromium-free passivated and oiled (CO)
This combination of surface treatment can be agreed upon where increased protection against white
rust or oiling as a means to aid in forming is required.Available dimensions
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Hot-dip galvanized steel strip in coils
Thickness Width Maximum outside diameter Inner diameter Coil weight
[mm] [mm] [mm] roughly [mm] 3) [t] max.
≥ 0.45 ≤ 3.5 ≥ 600 ≤ 800 2000 600 -
≥ 0.45 ≤ 3.5 > 800 1)
< 900 1)
2000 600 -
≥ 0.45 ≤ 3.5 ≥ 900 ≤ 1600 2) 2000 600 32
1)
Width range between > 800 and < 900 mm only upon request.
2)
With limited width tolerance of 1,580 mm max.
3)
Inner diameter of 500 mm upon request.
42Inspection and Testing
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
The products can be delivered with or without any test of compliance with the requirements of these
Technical Terms of Delivery and/or ordering standards.
Material test certificates
In the event a certificate is desired, one of the test certificates defined in EN 10204 is subject to agree-
ment at the time of the order.
Test unit
Specific tests are restricted to a test unit of 20 tons or a portion of 20 tons of hot-dip galvanized steel
strip of the same rolling unit. In the case of strip, a coil of more than 20 tons is considered as a test unit.
Scope of testing:
For each test unit, a series of tests is conducted to determine the following:
43
p Mechanical properties
p Coating adhesion
p Coating weight
Sample taking
Rolls from which samples are taken remain a constituent of the order. The right to select samples from
sheets is reserved by the employee responsible for the delivery certificate.
Performance of tests
Substrate testing
The tensile test is conducted in accordance with EN 10002-1 with samples of Form 2 (sample width
w = 20 mm, initial measured length L0 = 80 mm). Samples of mild steels, high-strength steels suita-
ble for cold forming and advanced high-strength steels are taken crosswise with respect to the di-
rection of rolling at a distance of at least 50 mm from the product edges. Structural steel samples are
taken in the longitudinal direction of rolling.Zinc coating test
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
The zinc coating is generally determined in the course of a continuous and non-destructive test.
The zinc coating is generally determined in the course of a continuous and non-destructive test.
The following procedure is followed for special tests and in cases of arbitration. The samples for the
gravimetric test of the zinc coating are taken across the width of the strip (see Figure 1). The samples
can be round or square and must have a surface of at least 50 cm 2. The gravimetric test is carried
out in accordance with the methods described in EN 10292, EN 10326, EN 10327 and EN 10336. The
weight of the zinc coating is determined during this test by chemical dissolution of three samples ta-
ken from an area of distribution across the width of the strip. The final value is the arithmetic mean
derived from the three surface samples. The lowest value from the three surface samples is the value
for the single surface sample.
Figure 1: Gravimetric test
44
50
50 50
b/ b/
2 2
Strip width B
Zinc adhesion test
Zinc coating adhesion is determined in a drop-ball impact test in accordance with SEP 1931/version
1991. Judgment is made based on a qualitative standard series, whereas the criterion of quality is
based on proper workability according to the respective application.
In cases of arbitration the zinc test is carried out by means of a bending test in accordance with
EURONORM 12. The diameter of the bending block or bending roll is applied in accordance with
Table 5. The bending angle is always 180°. The sample legs are pressed together in such a manner
that the coating is not damaged.
Repeat tests
EN 10021 applies. Repeat tests on coils are carried out at a distance of at least one coil turn, however
from 20 meters at the most from the end of the strip.Processing information
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
The following brief instructions are intended to provide assistance in processing hot-dip galvanized
steel strip. Our technical staff members are at your disposal to answer any of your questions.
Forming
Depending on the particular grade of hot-dip galvanized strip, it can be used for conventional for-
ming processes such as edging, bending, curling, flanging, stamping, crimping, roll-profiling, stretch
forming and deep drawing. The selection of materials depends on the demands on formability as well
as the final geometry and function of the work piece. The zinc coating and the surface are adapted to
the processing parameters. The properties of the zinc require that the drawing gap and the retraction
radius are enlarged in certain cases as compared to uncoated thin sheet. Altered flow behavior ma-
kes it necessary in some cases to adapt the hold-down force in forming processes.
Joining
45
Conventional thermal and mechanical joining and gluing processes are used as connecting tech-
niques, some of which, however, require adaptation of the processing parameters in order to take
into account special physical and chemical properties of the coatings. Hot-dip galvanized steel strip
is suitable for welding with common welding techniques. Special adjustment of the welding para-
meters and electrodes is necessary for this material when resistance welding (spot, projection or
stitch welding) is used. Thin zinc coatings simplify the welding process. The fumes generated during
welding should be exhausted. Corrosion protection in the welding area is optimized by means of a
suitable post-treatment process (such as zinc dust paint coating). Hot-dip galvanized sheet can be
soft-soldered or brazed. A metallically clean surface is a precondition that can be achieved with sui-
table fluxing agents. Proper filling of the joint is achieved with respective brazing metals. Corrosive
fluxing agents are to be carefully washed off after soldering. Mechanical joining techniques such as
screwing, riveting, crimping, flanging and clinching are not problematic and have the advantage that
they preserve the surface and maintain the anticorrosive properties. It is necessary to consider possi-
ble problems of contact corrosion when different materials are combined.
The significance of metal gluing is increasing in combination with other methods of joining. High-
strength connections are achievable with modern adhesives, even between oiled sheets. An examina-
tion of the surface systems, possible treatment processes and the adhesives themselves is advisable.Thermal rating
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Structural parts made of hot-dip galvanized steel strip can undergo long-term heat treatment up to
roughly 200–250 °C. Temperature stress that lasts longer than this can lead to negative effects in the
substrate and surface materials because of the diffusion reaction between the zinc coating and the
substrate.
Suitability for the application of coatings
Hot-dip galvanized steel strip in all of its surface grades lends itself well to the application of organic
coatings (such as paints or films). Surface MB or MC is the correct selection in the event of high or
higher demands on a uniform surface appearance after coating. Proper pretreatment is required in
order to achieve perfect adhesion. Surface phosphating pretreatment in the works provides an excel-
lent base for the adhesion of conventional organic coatings as long as the surfaces are clean.
46General notes
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Fretting corrosion
Mutual friction between strips of hot-dip galvanized steel during transportation can cause dark spots
on the zinc surface. These affect the appearance but do not adversely affect the quality of the corrosion
protection. The tendency toward fretting corrosion can be minimized by oiling the hot-dip-galvanized
steel strip.
Darkening
Hot-dip galvanized steel strip is generally intended for short-term processing. The degree of surface
darkening may vary when these grades are stored for a longer period of time. This affects the appea-
rance of the surface but does not adversely affect corrosion protection.
47
Formation of white rust
When hot-dip galvanized steel strip is subjected to humidity for a longer period of time with reduced
ventilation, a loose, mat gray to reddish material called white rust forms on the surface. Wide areas of
the material are attacked particularly when condensation water forms and wetness occurs between the
sheets or the coil layers.
There is no danger of white rust forming as long as the coils are stored properly. Temperature changes
during transportation and storage are critical.Diagram used to determine danger of white rust caused by condensation
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Example 1: Strip temperature of 8 °C, room temperature of 21 °C, relative humidity of 55% danger of white rust.
Example 2: Storage area of 19 °C, relative humidity of 50% minimum strip temperature of 11 °C required.
Temperature (°C) Relative air humidity
40% 50% 60% 70% 100%
25
1
20
2
15
10
48
Area of condensation
5
0
-5
Flatness
The strip is placed under tension when it is coiled. This tension causes deviations in the flatness of the
strip when it is downcoiled. A suitable straightening machine must be used to achieve flat condition of
the strip when delivered in coils. In some cases it improves the flatness of the material when paper in-
serts are applied during coiling. These are marked by flags placed on the end face. If paper inserts are
not desired or permitted, please specify this in the order.Hot-dip galvanized steel strip with
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
zinc/iron-coating (Galvannealed)
Hot-dip galvanized steel strip is a hot-dip refined product with Zn or ZnFe coating on both sides.
The strip is subjected to heat treatment immediately after being galvanized. The zinc coating reacts
with the substrate material and forms a ZnFe coating with approximately 8–12% Fe.
This manufacturing process was the forerunner of the generally known product name
GALVANNEALED (= GALVanized and ANNEALED).
Steel grades
All steel grades described in the section entitled Hot-dip galvanized steel strip are available with the
exception of complex-phase and TRIP steels.
The same guarantees apply to mechanical parameters, with the following exceptions:
49
p Statistical values lower by two units apply to the minimums for mild steels from grade DX54D and
high-strength steels.
p The guaranteed r values are decreased for all steel grades by 0.2.
p The guaranteed n90 value for steel grades DX56D and DX57D is decreased by 0.01.
The available dimensions are limited to a thickness range of 0.5 to 2.0 mm.ZF coating groups
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Coating groups
Zinc Coating in g/m2 on both sides min. Zinc coating thickness in µm per side
ZF coating group
Triple surface test Single surface test Typical value Area
ZF 80 80 70 5.5 4 – 10
ZF 100 100 85 7.0 5 – 12
ZF 120 120 100 8.0 6 – 13
A ZF coating of 100 g/m2 (on both sides) corresponds to a ZF layer thickness of approximately 7 µm
per side.
50Surface
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Hot-dip galvanized steel strip with a zinc/iron coating is delivered in Surface RA, RB and RC.
Surface quality
Surface quality R
Hot-dip galvanized steel strip with a zinc/iron coating is characterized by a mat gray surface that is
free of spangles.
Surface type
Typical surface A
Small pits, dark spots, stripe-shaped marks, and small passivation defects are acceptable on this type
of surface. Straightening and bending fractures and runoff waves may be visible.
Improved surface B
51
This type of surface is attained by rerolling. The inspected side may be characterized by a small
number of occurrences of fractures in stretch forming direction, finishing imprints, scratches, im-
pressions and slight passivation errors. The uninspected side of the material must at least meet the
requirements of Surface Type A.
Best surface C
This type of surface is also attained by rerolling. The inspected side does not negatively impact the
uniform appearance of a paint coat. The other side of the material must at least meet the requirements
of Surface Type B. Surface Type C is available for delivery up to 1.5 mm.
Roughness
As a standard, Surface types B and C are delivered with a medium roughness value ranging bet-
ween 1.0 and 1.9 µm. Determination of the mean Ra roughness value is subject to a wavelength limit
of 2.5 mm in accordance with EN 10049 (standard length of 12.5 mm).Subsequent surface treatment
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Hot-dip galvanized steel strip with a zinc/iron coating is normally delivered with an oiled (O) zinc/
iron coating. Galvannealed can be delivered upon request in chromium-free passivated (C) or chro-
mium-free passivated and oiled (CO). Depending on the defined micro-topography, difficult forming
stresses may make it necessary to increase the oil coating.
Oil amounts
Oiled approx. 1.2 g/m2 per side
Heavily oiled approx. 1.6 g/m2 per side
52Available dimensions
T echnic a l T e rm s o f D e l i v e ry • H o t-di p g a l v a ni z e d s te e l s tri p • 0 2 /2 0 1 2
Hot-dip galvanized ZF hot-rolled strip in coils
Thickness Width Maximum outside diameter Inner diameter Coil weight
[mm] [mm] [mm] roughly [mm] [t] max.
≥ 0.50 1) ≤ 2.0 ≥ 600 ≤ 800 2000 600 -
≥ 0.50 1)
≤ 2.0 > 800 2)
< 900 2)
2000 600 -
≥ 0.50 1) ≤ 2.0 ≥ 900 ≤ 1600 3) 2000 600 32
1
) Thicknesses below 0.5 mm only upon request.
2)
Width range between > 800 and < 900 mm only upon request.
3)
With limited width tolerance of 1,580 mm max.
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